1. Field of the Invention
The present invention relates to a lubricant supply method and a lubricant supply apparatus for supplying a lubricant to a tool holder clamp device provided on a spindle shaft of a machine tool such as a machining center.
2. Description of the Related Art
As a machine tool such as a machining center, there is known a machine tool with a tool automatic change device. The machine tool with the tool automatic change device includes a magazine with a plurality of tools received therein, and one of the tools received in the magazine can be gripped by the tool automatic change device and can be substituted for a tool mounted on a spindle shaft. The tool to be mounted onto the spindle shaft is clamped through a tool holder by a tool holder clamp device provided in the spindle shaft.
In the machine tool of this type, after a given workpiece is machined using a tool mounted on the spindle shaft, the tool is changed with another tool using the tool automatic change device; and, since then, the machining operation of the workpiece is proceeded while automatically changing the tools properly. And, when the machining operation is executed for a given time or by a given number of times, a lubricant is periodically supplied to the tool holder clamp device provided in the spindle shaft.
In the case of supplying the lubricant to the tool holder clamp device, due to the structure of the spindle shaft, it is difficult to supply the lubricant from inside the spindle shaft. For this reason, when supplying the lubricant to the tool holder clamp device, an operator manually supplies the lubricant from the front of the spindle shaft by greasing or by spraying.
However, in the above-mentioned conventional lubricant supply method in which an operator supplies lubricant by hand, there arises a problem that the operator must stop the machine tool each time the lubricant is supplied. Further, for example, in case where the operator omits to supply the lubricant, there arises another problem that the tool holder clamp device occurs an imperfect clamp, to thereby stop the machine tool.
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional lubricant supply method. Accordingly, it is an object of the invention to provide lubricant supply method and apparatus in which a lubricant can be supplied automatically to thereby be able not only to save the operator""s time and labor for supply of the lubricant but also to prevent occurrence of the imperfect clamp caused by the operator""s omission to supply the lubricant.
To attain the above object, according to the present invention, there is provided a method for supplying a lubricant in a machine tool, the machine tool including a spindle shaft equipped with a tool holder clamp device in the interior portion thereof and a tool automatic change device for changing a tool mounted on the spindle shaft with a tool stored in a magazine, the tool holder clamp device adapted to clamp a tool holder provided in the too, the method comprising the steps of: inserting a lubricant supply apparatus stored in the magazine to the spindle shaft through the tool automatic change device; and, supplying the lubricant to the tool holder clamp device from the lubricant supply apparatus inserted into the spindle shaft.
Further, there is provided an lubricant supply apparatus for supplying a lubricant in a machine tool, comprising: a lubricant tank filled with the lubricant; a tank holder portion on which the lubricant tank is mounted, the tank holder portion having a holder member adapted to be gripped by a tool automatic change device; and an injection holes supplying the lubricant filled in the lubricant tank to a tool holder clamp device of the spindle shaft, when the lubricant supply apparatus is inserted into a spindle shaft provided in the machine tool.